Proposal: Centralize Layout Mapping Logic

Reason

Mapping A2UI layout enums (like spaceBetween) to framework-specific values (like space-between in CSS or MainAxisAlignment.spaceBetween in Flutter) is currently handled inconsistently inside each renderer.

Design

1. Shared Constants: Create renderers/web_core/src/v0_9/common/layout.ts to host standard mapping functions for Web/CSS-based renderers.
2. Normalization: Provide mapJustify(val) and mapAlign(val) functions that return standard CSS values.
3. Refactor: Remove the redundant mapping logic from react_prototype and any future Angular/Lit renderers, importing from the centralized web_core location instead.

Key Files

• renderers/web_core/src/v0_9/common/layout.ts (New)
• renderers/react_prototype/src/basic_catalog/utils.ts